Electronic component desired voltage level comparison

ABSTRACT

A comparison circuit for comparing the desired voltage levels of electronic components and for disabling the supply of power to those components if the desired voltage levels are not equivalent. The comparison circuit receives the desired voltage level indication signals and provides a signal indicating whether the desired voltage levels are equivalent. If the desired voltage levels are not equivalent, the comparison circuit provides a signal indicating non equivalency to a power supply, wherein the power supply is disabled from supplying power so as not to damage the computer components from receiving power at a non allowable voltage level. The comparison circuit also provides an output signal indicative of an equivalent voltage level to the desired voltage levels if the desired voltage levels are equivalent. A power supply converter supplies power to the components at a voltage level as indicated by the output signal. The comparison circuit can be implemented in a computer system such as a multiprocessor computer system wherein each processor module provides a desired voltage level indication signal to the comparison circuit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention in general relates to a supply of power to electronicsystem components and in particular to a comparison of the desiredvoltage levels of that supply.

2. Description of the Related Art

Computer systems are information handling electronic systems which canbe designed to give independent computing power to one user or aplurality of users. Computer systems may be found in many formsincluding, for example, mainframes, minicomputers, workstations,servers, personal computers, internet terminals, notebooks, and embeddedsystems. Personal computer (PC) systems, such as the InternationalBusiness Machines (IBM) (tm) compatible PC systems, include desk top,floor standing, or portable versions. A typical PC system includes aprocessor, associated memory and control logic, and a number ofperipheral devices that provide input and output for the system. Suchperipheral devices often include display monitors, keyboards, mouse-typeinput devices, floppy and hard disk drives, CD-ROM drives, printers,network capability cards, terminal devices, modems, televisions, sounddevices, voice recognition devices, electronic pen devices, and massstorage devices such as tape drives, CD-R drives, or DVDs. Other typesof computer systems may also include similar devices as well.

Computer systems and other types of electronic systems employ powersupplies to provide power for a system within required parameters. Sometypes of power supplies convert alternating current (AC) power to directcurrent (DC) power at regulated voltage levels required by the systemfor proper operation. Such voltage levels may include +/−12 VDC, +/−5VDC, and +/−3.3 VDC. Some power supplies convert DC power having a firstset of parameters to DC power having a second set of parameters. Somepower supplies utilize batteries as the original power source.

Computer system components such as processors, memory devices, and otherelectronic circuits require power at specific voltage levels or rangesin order to operate properly. To ensure that the proper voltage level isprovided, some components of a system may provide a voltage levelindication signal to the power supply to indicate a desired voltagelevel for the supply of power to the component and, in some cases, othercomponents of the system. An example of one such system is found in thepatent application entitled “Voltage Supply Regulation UsingMaster/Slave Timer Circuit Modulation,” inventor Alan E. Brown, Ser. No.08/991,087, filed on Dec. 15, 1997, and having a common assignee, all ofwhich is hereby incorporated by reference in its entirety.

For some electronic systems, it is economically desirable to limit thenumber of power supplies in the system. Accordingly, power for multiplecomponents may be supplied from a single power supply. With suchsystems, proper design and manufacture techniques can usually ensurethat all components of the system require the same voltage levels ofpower. However, the practical realities of today's computer industry areof low cost part assembly stores and frequent component upgrades. Withsuch realities, compatibility of voltage requirements are not alwaysassured. Such voltage level requirement miss-matches can lead tocomponent substandard performance or component failure. An example of asystem where a problem may occur is with multiprocessor computers wherethe different processors may have different desired voltage levels forthe supply of power to each processor.

What is needed is a circuit to compare the desired voltage levels ofdifferent components and to provide indications of those comparisons inorder to prevent damage to components in the event of non equivalentdesired voltage levels.

SUMMARY OF THE INVENTION

It has been discovered that a circuit that compares the desired voltagelevels of power for components of an electronic system and provides anindication of the comparison can achieve numerous advantages. Oneadvantage is that such an indication can be used to disable the supplyof power to electronic components of a system if an indication of nonequivalency is provided. It can also be used to provide a visualindication of such a condition. If the desired voltage levels areequivalent, an indication of an equivalent desired voltage level can beprovided to a power supply to power multiple electronic components fromthe power supply at an equivalent desired voltage level.

In one aspect of the invention, a computer system includes a pluralityof computer components and a comparison circuit having a plurality ofinputs. Each input is for receiving an indication signal indicating adesired voltage level of power for a respective computer component. Thecomparison circuit also has an output. The computer system also includesa power supply configured to supply power to the respective computercomponents. The comparison circuit provides at its output a disablesignal to disable the power supply from supplying power to therespective computer components as a result of a non equivalency in thedesired voltage levels as determined by the comparison circuit.

In another aspect of the invention, a computer system includes means forreceiving a plurality of indications, each indicating a desired voltagelevel of power for a respective computer component. The computer systemalso includes means for disabling a supply of power to the respectivecomputer components as a result of a non equivalency in the desiredvoltage levels.

In another aspect of the invention, a method for comparing desiredvoltage levels of electronic components includes receiving a pluralityof indication signals. Each indication signal received indicates adesired voltage level of power for a respective electronic component.The method also includes comparing the desired voltage levels of theindication signals received and disabling a power supply from supplyingpower to the respective electronic components as result of a nonequivalency in the desired voltage levels as determined by thecomparison.

In another aspect of the invention, a comparison circuit includes afirst input for receiving a first indication signal indicating a desiredvoltage level of power for a first electronic component and a secondinput for receiving a second indication signal indicating a desiredvoltage level of power for a second electronic component. The comparisoncircuit also includes an output for providing an output indicationsignal indicating an equivalent desired voltage level as a result of adetermination that the desired voltage levels are equivalent.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood, and its numerousobjects, features, and advantages made apparent to those skilled in theart by referencing the accompanying drawings.

FIG. 1 is a block diagram of one example of an electronic systemimplementing a comparison circuit according to the present invention.

FIG. 2 is a circuit diagram of one example of a comparison circuitaccording to the present invention.

FIG. 3 is a block diagram of one example of a multiprocessor computersystem.

The use of the same reference symbols in different drawings indicatesidentical items unless otherwise indicated.

DETAILED DESCRIPTION

The following sets forth a detailed description of a mode for carryingout the invention. The description is intended to be illustrative of theinvention and should not be taken to be limiting.

FIG. 1 shows a block diagram of one example of an electronic systemincorporating a comparison circuit according to the present invention.The electronic system shown in FIG. 1 is a multi-processor computersystem 101 such as the PRECISION 610 WORKSTATION sold by the DELLCOMPUTER CORP. Computer system 101 includes two processor modules 104and 106. A processor module typically includes a processor circuit suchas a processor circuit conforming to the INTEL X86 architecture or otherprocessor architectures. Processor modules 104 and 106 also include L2caches which can either be integrated on a semiconductor chip with theprocessor or implemented separately. With some systems, a processormodule is implemented on a daughter card and includes terminations andcircuitry for local processor busses as well as other conventionalcircuitry. With other systems, a processor module is located on acomputer system motherboard (not shown). An example of a processormodule is a PENTIUM II (tm) cartridge sold by the INTEL CORPORATION.

Each processor module 104 and 106 receives power from a DC power supply109 which includes a DC-to-DC voltage converter. DC power supply 109receives DC power from power supply 113 which includes an AC to DCrectifier for converting AC power to DC power. The DC-to-DC converter ofpower supply 109 may have one of a number of conventional convertertopologies such as linear converter topologies and switching convertertopologies including e.g. buck, boost, forward converter, push-pull,half and full bridge, fly-back, and multiphase. Power supply 109 mayalso receive power from a battery power source. The DC-to-DC converterof DC power supply 109 provides at its output 121 DC power at aregulated voltage level which is supplied to components of the computersystem including components of the processor module. With some systems,DC power supply 109 is mounted on the system mother board (not shown)and power supply 113 is mounted in the system chassis (not shown). Withother systems, the components of power supplies 113 and 109 areimplemented as an integrated power supply.

In FIG. 1, processor modules 104 and 106 each include output terminalsconfigured to provide a voltage level indication signal. Theseindication signals (labeled VID1 and VID2) provide indications of adesired voltage level for the supply of power to components of theprocessor module such as the L2 cache. With some systems, a “desired”voltage level for a component may be a required voltage level, whereinthe component does not operate properly if not supplied at that voltagelevel. With other components, the desired voltage level may indicate avoltage level where the component operates at optimum performance. InFIG. 1, each voltage reference indication signal includes five paralleldiscrete signals providing a digital value indicating a desired voltagelevel. Each possible digital value of an indication signal correspondsto a specific voltage level. With other systems, the voltage indicationsignal may have a different number of discrete signals or have otherforms such as analog and serial digital forms. With other processormodules, the processor circuit or other components may provide thedesired voltage indication signals.

Comparison circuit 127 receives both voltage level indication signalsfrom processor modules 104 and 106 and provides signals that indicate aresult of the comparison. If the voltage reference indication signalsare not determined to be equivalent as a result of the comparison, thenthe comparison circuit places the V_(dis) signal in a state thatindicates a non equivalency in the desired voltage levels. In responseto receiving a V_(dis) signal in a state indicating a non equivalency inthe desired voltage levels, the control circuitry (not shown) of powersupply 113 disables power supply 113 from supplying DC power to powersupply 109, thereby disabling power supply 109 from supplying power atits output 121. With other systems, the V_(dis) signal is provided topower supply 109 wherein in response to receiving a V_(dis) signal in astate indicating a non equivalency, the control circuitry (not shown) ofpower supply 109 disables power supply 109 from supplying DC power atoutput 121.

As a result of a determination that the desired voltage levels areequivalent based upon the comparison of the desired voltage levels, thecomparison circuit provides an output indication signal (VID_(out)) thatincludes 5 parallel discrete signals providing a digital valueindicating an equivalent voltage level to the two desired voltage levelsas indicated by the VID signals received from processor modules 104 and106. In FIG. 1, a digital to analog (D/A) converter 125 converts thedigital VID_(out) signal into an analog V_(ref) signal having a voltagelevel indicative of the equivalent voltage. An example of a D/Aconverter is found in the U.S. patent application entitled “VoltageSupply Regulation Using Master/Slave Timer Circuit Modulation,” asdescribed in the “Background” section above. With some systems, the D/Aconverter may be integrated with the comparison circuit or integratedwith the control circuitry (not shown) of power supply 109. Also, thecomparison circuit may be integrated with the control circuitry (notshown) of power supply 113 or power supply 109. For comparison circuitsproviding other than a digital voltage level indication signal, a D/Aconverter would not be utilized. With other systems, D/A converterswould be located between the comparison circuit and each processormodule wherein the comparison circuit would receive analog indicationsignals and provide the VID_(out) signal in analog form to the DCconverter of power supply 109.

The voltage level of output 121 is controlled by a V_(ref) signal. InFIG. 1, V_(ref) is an analog signal having a voltage level at (orproportional to) an equivalent voltage to the desired voltage levels.With some types of power supplies, V_(ref) is an input into an erroramplifier (not shown) of the secondary side control circuitry (notshown) of the power supply 109 DC-to-DC converter. With other converterssuch as switching converters, V_(ref) can be inputted into the primarycontrol converter circuitry (not shown) and is used to control the dutycycle of the switching signal which controls the voltage level ofconverter output 121. With other converters, the V_(ref) signal may haveother forms. Those of skill in the art will recognize that any number ofconventional techniques can be utilized for controlling the voltagelevel of the output of a DC-to-DC converter with a reference signal.

FIG. 2 shows a circuit diagram of one example of a comparison circuit.Comparison circuit 127 includes a programmable array logic (PAL) device205 such as the PAL22V10LV-25 sold by ATMEL INC. Input terminals I1-I5make up a first input for receiving a voltage reference indicationsignal (VID1) from processor module 104 and input terminals I6-I10 makeup a second input for receiving a second voltage reference indicationsignal (VID2) from processor module 106. The signal lines connected tothe input terminals are connected to pull-up resistors 207 which areeach connected on another end to a +5 VDC auxiliary stand-by powersource (5V₁₃SB) (not shown) of power supply 113. Output terminals *IO9,*IO6, and *IO2-*IO4 provide the VID_(out) signal. Output terminal *IO8provides the V_(dis) signal.

Comparison circuit 127 also includes an LED 215 for providing a visualindication of non equivalent desired voltage levels.

PAL 205 is programmed such that when the digital value of VID1 is equalto VID2, the PAL provides signal VID_(out) with a value equal to that ofVID1 and places the V_(dis) signal in a logical 0 state to indicate thatthe desired voltage levels are equivalent. Accordingly, *V_(dis) isprovided with a high voltage level such that LED 215 does notilluminate.

If the digital value of VID1 does not equal the digital value of VID2,then PAL 205 places V_(dis) at a logical 1 state indicating that thedesired voltages are not equivalent. The V_(dis) signal in a logical 1state disables power supply 113 (and consequently power supply 109)thereby preventing the components of the processor modules fromoperating and preventing damage to the components of computer system101. Also, as a result of determining that the desired voltages are notequal, PAL 205 places *V_(dis) in a low voltage state, therebyilluminating LED 215 to provide a visual indication that the desiredvoltages are not equivalent.

In the above exemplary operation of PAL 205, the V_(dis) signal beingplaced in a state indicating that the desired voltage levels are “nonequivalent” requires that the VID1 and VID2 signals not be equal to eachother. However, PAL 205 may be programmed such that the voltage levelindication signals do not have to be equal for the V_(dis) signal toindicate that the two voltage levels are “equivalent.” For example, PAL205 could be programmed such that if the two voltage level indicationsignals VID1 and VID2 were within a predetermined digital range of eachother (such as a digital range of 2 of each other e.g. VID1=01110 andVID2=01100), PAL 205 would place the V_(dis) signal in a stateindicating equivalency and provide the VID_(out) signal with a valueindicative of either one of the input VID signal values or a value inbetween the input VID signal values. If the desired voltage levelindication signals were outside of the predetermined digital range ofeach other (e.g. outside a digital value of 2), PAL 205 would place theV_(dis) signal in a state indicating a non equivalency. Such a programcould be utilized where the desired voltage level indication signals ofone type or make of component is not 100% compatible with the voltagelevel reference signals of the other components. Also, such a programcould be utilized where the incremental difference in the levels of thevoltage level indication signals are less than the tolerances of therequired voltages for the components.

Where the desired voltage level indication signal takes other forms, thespecified parameter that the two signals would be required to be withinto provide an indication of equivalency would also have a differentform. For example, if the voltage level indication signals have ananalog form, the specified parameter may be that the indication signalsmust be within a specific voltage level (e.g.±0.05V) of each other.

Although FIGS. 1 and 2 show a comparison circuit with only two inputs,each for receiving a desired voltage level indication signal, othercomparison circuits may include more than two inputs for receivingindication signals, thus allowing the comparison circuit to receiveindication signals from more than two electronic components. Forexample, referring ahead to FIG. 3, a comparison circuit for computersystem 101 may include four inputs, an input for each processor module104 and 106, an input for system memory 309, and an input for Flash ROM311.

Referring back to FIG. 2, for those systems where not all of thecomparison circuit inputs for receiving indication signals are operablycoupled to receive an indication signal indicating a desired voltagelevel for a computer component, PAL 205 can determine from the state ofthe input whether the input is not operably coupled to receive anindication signal indicating a desired voltage level. For example, ifinput terminals I1-I5 are not receiving a voltage level indicationsignal, then those input terminals will be approximately at the +5V₁₃SBlevel. Upon determining that only the second input is receiving avoltage level indication signal, PAL 205 provides a VID_(out) signalindicating a voltage level equal to VID2. Consequently, if only thefirst input is receiving a voltage level indication signal and thesecond input is not, then VID_(out) will equal VID1. If the comparisoncircuit includes more than two inputs and one of the inputs is notoperably coupled to receive a signal indicating a desired voltage levelof a computer component, a comparison circuit can be configured toprovide an indication of non equivalency based upon a comparison of onlythe received indication signals. For example, if a comparison circuitincludes four inputs, but only two inputs are operably coupled toreceive indication signals of computer components, then the comparisoncircuit's indication of non equivalency will be based upon the values ofthe two voltage level indication signals received. An example of asituation is where an input is not operably coupled to receive anindication signal is where a termination card occupies a processormodule daughter card slot.

Based upon the teachings herein, those of skill in the art willappreciate that a comparison circuit performing the above operations canbe implemented in other ways in addition to those shown in the Figuresand described above. For example, a comparison circuit may beimplemented with logic hardware, either with separate components or asan integrated component. Also, the comparison circuit may be implementedwith other types of programmable devices. Where the desired voltagelevel indication signals have an analog form, an analog comparisoncircuit may be utilized.

FIG. 3 shows a block diagram of computer system 101 which is amulti-processor computer system. An example of a multi-processorcomputer system is the PRECISION 610 WORKSTATION sold by the DELLCOMPUTER CORP. A system memory 309 is operably coupled to the processorsof processor modules 104 and 106 via a local computer bus. Computersystem 101 also includes a Flash ROM 311 and keyboard controller 313operably coupled to the processors of processor modules 104 and 106 viaan ISA computer bus, PCI computer bus, and local computer bus, all ofwhich are conventional. Computer system 101 also includes a remoteaccess card for operably coupling computer system 101 to a computernetwork.

The comparison circuit may be mounted on the system planar board (notshown) of computer system 101 adjacent to the processor module slots.However, the comparison circuit may be physically implemented in otherways with different computer systems.

FIG. 3 is presented as one example of a computer system thatincorporates a comparison circuit such as comparison circuit 127.However, based upon the teachings herein, those of skill in the art willappreciate that a comparison circuit may be implemented with other typesof computer systems or other electronic systems.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art that,based upon the teachings herein, changes and modifications may be madewithout departing from this invention and its broader aspects and,therefore, the appended claims are to encompass within their scope allsuch changes and modifications as are within the true spirit and scopeof this invention.

What is claimed is:
 1. A computer system including a plurality ofcomputer components comprising: a comparison circuit having a pluralityof inputs, each input for receiving an indication signal indicating adesired voltage level of power for a respective computer component, thecomparison circuit having an output; a power supply configured to supplypower to the respective computer components; wherein the comparisoncircuit provides at its output a disable signal to disable the powersupply from supplying power to the respective computer components as aresult of a non equivalency in the desired voltage levels as determinedby the comparison circuit.
 2. The computer system of claim 1 wherein afirst indication signal is provided by a first processor module and asecond indication signal is provided by a second processor module. 3.The computer system of claim 2 wherein the first and second processormodules each include an L2 cache configured to receive power from thepower supply.
 4. The computer system of claim 1 wherein each indicationsignal provides a digital value indicating a desired voltage level ofpower for the respective computer component.
 5. The computer system ofclaim 1 wherein a determination of a non equivalency in the desiredvoltage levels requires that the indication signals not be equal.
 6. Thecomputer system of claim 1 wherein a determination of a non equivalencyin the desired voltage levels requires that the indication signals notbe within a specified parameter of each other.
 7. The computer system ofclaim 1 further comprising a light electrically coupled to thecomparison circuit for providing an indication that the desired voltagelevels are not equivalent.
 8. The computer system of claim 1 wherein,the comparison circuit provides an output indication signal indicatingan equivalent desired voltage level as a result of a determination thatthe desired voltage levels are equivalent.
 9. The computer system ofclaim 8 wherein a determination that the desired voltage levels areequivalent requires that the indication signals be equal.
 10. Thecomputer system of claim 8 wherein a determination that the desiredvoltage levels are equivalent requires the indication signals to bewithin a specified parameter of each other.
 11. The computer system ofclaim 8 further wherein: the power supply includes a DC-to-DC converter,the power supply has an input for receiving a reference indicationsignal dependent upon the output indication signal provided by thecomparison circuit, wherein the power supply supplies at its output,power at a regulated DC voltage level that is dependent upon thereference indication signal.
 12. The computer system of claim 11 furthercomprising: a digital to analog converter having an input for receivingthe output indication signal and an output for providing the referenceindication signal, the reference indication signal having an analoglevel corresponding to a digital value of the output indication signal.13. The computer system of claim 1 wherein as a result of adetermination that only one input of the plurality is receiving anindication signal indicating a desired voltage level, the comparisoncircuit provides an output indication signal indicating the desiredvoltage level as determined by the indication signal received by theonly one input.
 14. The computer system of claim 13 wherein thecomparison circuit determines that the only one input is receiving anindication signal by the remaining inputs of the plurality being at aparticular input state.
 15. The computer system of claim 1 wherein as aresult of a determination that only a set of at least one of theplurality of inputs are receiving indication signals indicating desiredvoltage levels and as a result of a determination that the desiredvoltage levels received via the set are equivalent, the comparisoncircuit provides an output indication signal indicating an equivalentdesired voltage level.
 16. The computer system of claim 1 furthercomprising: a second power supply having an output for providing powerto the power supply, the second power supply having an input forreceiving a signal dependent upon the disable signal, wherein thedisable signal being in a state indicating a non equivalency in thedesired voltage levels disables the second power supply from supplyingpower to the power supply thereby disabling the power supply fromsupplying power to the respective components.
 17. The computer system ofclaim 1 wherein each indication signal includes a plurality of paralleldiscrete signals and wherein each input includes a plurality of inputterminals for receiving the parallel discrete signals.
 18. The computersystem of claim 1 wherein: the disable signal has a first stateindicative that the desired voltage levels are not equivalent.
 19. Thecomputer system of claim 18 wherein the disable signal being in thefirst state requires the indication signals not to be equal.
 20. Thecomputer system of claim 18 wherein the disable signal being in thefirst state requires the indication signals not to be within a specifiedparameter of each other.
 21. The computer system of claim 8 furthercomprising: a second output including a plurality of output signalterminals; wherein the output indication signal includes a plurality ofparallel discrete signals, each provided on one of the plurality ofoutput signal terminals.
 22. The computer system of claim 1 wherein thecomparison circuit further includes: a programmable array logic devicehaving a plurality of input terminals for receiving the indicationsignals and at least one output terminal for providing the disablesignal.
 23. The computer system of claim 1 wherein the plurality ofinputs of the comparison circuit include at least three inputs.
 24. Acomputer system comprising: means for receiving a plurality ofindications, each indicating a desired voltage level of power for arespective computer component; means for disabling a supply of power tothe respective computer components as a result of a non equivalency inthe desired voltage levels.
 25. A method for comparing desired voltagelevels of electronic components comprising: receiving a plurality ofindication signals, each indication signal received indicating a desiredvoltage level of power for a respective electronic component; comparingthe desired voltage levels of the indication signals received; anddisabling a power supply from supplying power to the respectiveelectronic components as result of a non equivalency in the desiredvoltage levels as determined by the comparison.
 26. The method of claim25 wherein disabling the power supply further includes: providing adisable signal in a first state indicating that the desired voltagelevels are not equivalent.
 27. The method of claim 26 wherein theproviding the disable signal in the first state further includes:determining that the indication signals are not equal; and providing thedisable signal in the first state as a result thereof.
 28. The method ofclaim 26 wherein the providing the disable signal in the first statefurther includes: determining that the indication signals are not withina specified parameter of each other; and providing the disable signal inthe first state as a result thereof.
 29. The method of claim 25 furthercomprising: illuminating a light as a result of the desired voltagelevels not being equivalent.
 30. The method of claim 25 furthercomprising: providing power to the respective components at anequivalent desired level as a result of the desired levels beingequivalent.
 31. The method of claim 30 wherein providing power to therespective components at the equivalent desired level further includes:providing an indication signal indicating the equivalent desired voltagelevel to the power supply.
 32. The method of claim 25 furthercomprising: providing power at a desired level indicated by a firstindication signal in response to determining that only a firstindication signal is being received.